(A) PBMC of tolerant patient 002002 were mixed with varying amounts (0–10 μL) of donor type HLA-B62 (open circle, p37MA+), third party HLA–B57 (open square, p37MA+) or self HLA-A1 (filled triangle, p37MA−)-coated single antigen beads before addition of TT/DT and injected into the mouse footpad. Net swelling was determined as in Figure 1A. The maximum percentage inhibition of response with recall TT/DT (0 beads) versus the response with 10 μL of single antigen beads was calculated as described in the methods and is 60% with B57 beads and 63% with B62 beads. Peptides: PBMC were co-injected into the mouse footpad with recall antigen TT/DT and 1000 ng of HLA-B62 allopeptide p37MA (DSDAASPRMAPRAPWIEQ) or HLA-B37 self peptide p37TE (DSDAASPRTEPRAPWIEQ). The percentage inhibition of recall antigen response with donor peptide is 68%. Patient 002002 = HLA A1, 2; B37, 60; DR 4, 13; donor type: A1, 2; B44, 62; DR 4, 13. (B) Indirect pathway tvDTH response to single antigen-beads detects stronger sensitization to a DSA+ as compared with DSA− donor HLA antigens. PBMC from CR patient 002048 were mixed with donor HLA-A2 (circles), HLA-A1 (squares) or HLA-B57 (inverted triangle)-coated single antigen beads and injected into a CB17 SCID mouse footpad. Net swelling was determined as in Figure 1A. Mean fluorescent intensity (MFI) values for a contemporaneous serum sample of the same subject tested using HLA-A2 (gray circle)-, HLA-A1 (gray square)- or HLA-B57 (gray inverted triangle)-coated single antigen beads are shown on the right. Patient 002048 = HLA-A11, 25; B18, 51;DR 9, 15 Donor = HLA-A1, 2; B7, 57; DR 11,15 (mismatch in bold).